ST_OffsetCurve()

Datum ST_OffsetCurve

(

PG_FUNCTION_ARGS

)

Definition at line 1084 of file postgis/lwgeom_geos.c.

References geos_intersection(), gserialized_from_lwgeom(), gserialized_get_type(), LINETYPE, lwgeom_as_lwline(), lwgeom_free(), lwgeom_from_gserialized(), lwgeom_is_empty(), lwgeom_offsetcurve(), PG_FUNCTION_INFO_V1(), and text2cstring().

Referenced by ST_GeneratePoints().

{
        GSERIALIZED     *gser_input;
        GSERIALIZED *gser_result;
        LWGEOM *lwgeom_input;
        LWGEOM *lwgeom_result;
        double size;
        int quadsegs = 8; /* the default */
        int nargs;

        enum
        {
                JOIN_ROUND = 1,
                JOIN_MITRE = 2,
                JOIN_BEVEL = 3
        };

        static const double DEFAULT_MITRE_LIMIT = 5.0;
        static const int DEFAULT_JOIN_STYLE = JOIN_ROUND;
        double mitreLimit = DEFAULT_MITRE_LIMIT;
        int joinStyle  = DEFAULT_JOIN_STYLE;
        char *param = NULL;
        char *paramstr = NULL;

        /* Read SQL arguments */
        nargs = PG_NARGS();
        gser_input = PG_GETARG_GSERIALIZED_P(0);
        size = PG_GETARG_FLOAT8(1);

        /* Check for a useable type */
        if ( gserialized_get_type(gser_input) != LINETYPE )
        {
                lwpgerror("ST_OffsetCurve only works with LineStrings");
                PG_RETURN_NULL();
        }

        /*
        * For distance == 0, just return the input.
        * Note that due to a bug, GEOS 3.3.0 would return EMPTY.
        * See http://trac.osgeo.org/geos/ticket/454
        */
        if ( size == 0 )
                PG_RETURN_POINTER(gser_input);

        /* Read the lwgeom, check for errors */
        lwgeom_input = lwgeom_from_gserialized(gser_input);
        if ( ! lwgeom_input )
                lwpgerror("ST_OffsetCurve: lwgeom_from_gserialized returned NULL");

        /* For empty inputs, just echo them back */
        if ( lwgeom_is_empty(lwgeom_input) )
                PG_RETURN_POINTER(gser_input);

        /* Process the optional arguments */
        if ( nargs > 2 )
        {
                text *wkttext = PG_GETARG_TEXT_P(2);
                paramstr = text2cstring(wkttext);

                POSTGIS_DEBUGF(3, "paramstr: %s", paramstr);

                for ( param=paramstr; ; param=NULL )
                {
                        char *key, *val;
                        param = strtok(param, " ");
                        if ( param == NULL ) break;
                        POSTGIS_DEBUGF(3, "Param: %s", param);

                        key = param;
                        val = strchr(key, '=');
                        if ( val == NULL || *(val+1) == '\0' )
                        {
                                lwpgerror("ST_OffsetCurve: Missing value for buffer parameter %s", key);
                                break;
                        }
                        *val = '\0';
                        ++val;

                        POSTGIS_DEBUGF(3, "Param: %s : %s", key, val);

                        if ( !strcmp(key, "join") )
                        {
                                if ( !strcmp(val, "round") )
                                {
                                        joinStyle = JOIN_ROUND;
                                }
                                else if ( !(strcmp(val, "mitre") && strcmp(val, "miter")) )
                                {
                                        joinStyle = JOIN_MITRE;
                                }
                                else if ( ! strcmp(val, "bevel") )
                                {
                                        joinStyle = JOIN_BEVEL;
                                }
                                else
                                {
                                        lwpgerror("Invalid buffer end cap style: %s (accept: "
                                                "'round', 'mitre', 'miter' or 'bevel')", val);
                                        break;
                                }
                        }
                        else if ( !strcmp(key, "mitre_limit") ||
                                  !strcmp(key, "miter_limit")    )
                        {
                                /* mitreLimit is a float */
                                mitreLimit = atof(val);
                        }
                        else if ( !strcmp(key, "quad_segs") )
                        {
                                /* quadrant segments is an int */
                                quadsegs = atoi(val);
                        }
                        else
                        {
                                lwpgerror("Invalid buffer parameter: %s (accept: "
                                        "'join', 'mitre_limit', 'miter_limit and "
                                        "'quad_segs')", key);
                                break;
                        }
                }
                POSTGIS_DEBUGF(3, "joinStyle:%d mitreLimit:%g", joinStyle, mitreLimit);
                pfree(paramstr); /* alloc'ed in text2cstring */
        }

        lwgeom_result = lwgeom_offsetcurve(lwgeom_as_lwline(lwgeom_input), size, quadsegs, joinStyle, mitreLimit);

        if (lwgeom_result == NULL)
                lwpgerror("ST_OffsetCurve: lwgeom_offsetcurve returned NULL");

        gser_result = gserialized_from_lwgeom(lwgeom_result, 0);
        lwgeom_free(lwgeom_input);
        lwgeom_free(lwgeom_result);
        PG_RETURN_POINTER(gser_result);
}

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